Tetrachloroethylene oxide
From Wikipedia, the free encyclopedia
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| Names | |
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| IUPAC name
tetrachlorooxirane | |
| Other names
Perchloroethylene oxide (PCEO), Epoxyperchlorovinyl, Tetrachloroepoxyethane | |
| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
PubChem CID |
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| UNII | |
CompTox Dashboard (EPA) |
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| Properties | |
| C2Cl4O | |
| Molar mass | 181.82 g·mol−1 |
| Appearance | liquid |
| Density | 1.72 g/cm3[1] |
| Melting point | –58 °C[2] |
| Boiling point | 110 °C [1] |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Tetrachloroethylene oxide, perchloroethylene oxide (PCEO) or tetrachlorooxirane, is the perchlorinated analogue of ethylene oxide and a proposed metabolite of tetrachloroethylene.[3] It is a halogenated epoxide with the formula C2Cl4O. Tetrachloroethylene oxide is fairly stable but rearranges to trichloroacetyl chloride at higher temperatures.[4]
The synthesis of tetrachloroethylene oxide via the oxidation of tetrachloroethylene was described by the French chemist A. Besson in 1894. He identified the compound as the epoxide of tetrachloroethylene, noted its boiling point as 110 °C and named it "oxide of perchlorinated ethylene" (oxyde d'éthylène perchloré).[5]
Tetrachloroethylene oxide was later synthesised by the English chemist Frederick William Kirkbride in 1940, by exposing a mixture of oxygen and chlorine in tetrachloroethylene to UV light.[6]
Tetrachloroethylene oxide can be obtained by the direct oxidation of tetrachloroethylene under UV light.[4]
Reactions
Unlike most epoxides, PCEO does not polymerise.[4]
PCEO reacts with methanol, with mercury(II) chloride as the catalyst, giving methyl trichloroacetate and hydrogen chloride:[2]
- C2Cl4O + CH3OH → CH3O(CO)CCl3 + HCl
PCEO reacts with methanolic potassium hydroxide to give potassium oxalate.[2] It is slowly decomposed by dilute acid or base solutions, giving off carbon monoxide, carbon dioxide and hydrogen chloride which was possibly from the further decomposition of the intermediate oxalyl chloride.[2]